Fix fcntl module to accept 'unsigned long' type commands for ioctl(2).
Although POSIX says the type is 'int', all BSD variants (including Mac OS X)
have been using 'unsigned long' type for very long time and its use predates
the standard long enough. For certain commands (e.g., TIOCSWINSZ, FIONBIO),
the Python value may get sign-extended on 64-bit platforms (by implicit type
promotion) and it causes annoying warnings from kernel such as this:
WARNING pid 24509 (python2.6): ioctl sign-extension ioctl ffffffff8004667e
Approved by: python (maintainer timeout)